Fix spurious warnings from unwise condition order in inlined code

Fix spurious warnings from unwise condition order in inlined code

These are both conditions having the form (and A B) where A is
side-effect-free and B may be known to be nil at compile time.
The compiler will then warn about A being useless and thrown away.
The fix is to test B first.

* lisp/gnus/gnus.el (gnus-method-to-server):
Test `(not no-enter-cache)` first.
(gnus-server-get-method): Test `group` first.